Field of the Invention
The present inventions relate to methods and systems for illuminating, obtaining images of, and determining the shape and position of structures within an eye, and in particular, the cornea, natural human crystalline lens and adjacent structures of the eye. More particularly, the present inventions relate to variably controlled scanning of laser light illumination of such structures, controlled and predetermined digital capture of the images of the illuminated structures with an accurately calibrated digital camera and the creation of enhanced digital composite images of the illuminated structures.
Description of the Related Art
Presbyopia most often presents as a near vision deficiency, the inability to read small print, especially in dim lighting after about 40-45 years of age. Presbyopia, or the loss of accommodative amplitude with age, relates to the eye's inability to change the shape of the natural crystalline lens, which allows a person to change focus between far and near, and occurs in essentially 100% of the population. Accommodative amplitude has been shown to decline with age steadily through the fifth decade of life.
Cataracts, or the condition when the natural crystalline lens becomes opaque and clouds vision, occurs in millions of people per year and are treated effectively with surgical techniques, such as ultrasonic phacoemulsification pioneered by Kelman 30 years ago. Although the techniques have been refined over the years, safety concerns from ocular trauma, especially to the corneal endothelium from the ultrasonic energy required to break up a hardened cataract, is undesirable; especially for those with a compromised corneal endothelium, such as those with Fuchs Dystrophy. Moreover, the use of lasers in the treatment of cataracts has a further issue. Cataracts scatter light, including laser light, and thus, can prevent a laser treatment beam from having the desired tissue effect. Moreover, the light scattering effect of cataracts and other opacifications can make optically determining the position and shape of the lens difficult.
The established treatment for cataracts is the removal of the opacified human crystalline lens and its replacement with an intraocular lens (“IOL”). In general, IOLs include a small plastic lens with plastic side struts, called haptics, to hold the lens in place within the capsular bag inside the eye. Exemplary types of IOLs include monofocal lenses, multifocal IOLs which provide the patient with multiple-focused vision at far and reading distance, and accommodative IOLs which provide the patient with visual accommodation. The flexible nature of many IOLs enables them to be rolled and/or folded up for insertion into the lens capsule.
The removal of the opacified natural crystalline lens and replacement with a lens replacement material, such as an IOL, presently employs a capsulorhexis and/or a capsulotomy procedure. A capsulorhexis generally includes of the removal of a part of the anterior lens capsule and the creation of a hole or opening in the lens capsule, which results, at least in part, from a tearing action. A capsulotomy generally includes of a cutting of the lens capsule, without or with minimum tearing of the lens capsule. Thus, to remove the opacified natural lens material, the lens capsule is opened. There are several known techniques for performing a capsulorhexis and a capsulotomy, including the use of a Fugo plasma blade.
Recently laser systems and methods for treating of cataracts, presbyopia, performing capsulotomies, and for the sectioning and removal of natural crystalline lens material have been developed and introduced. Examples of such innovative and novel systems and methods are found in commonly assigned published patent applications US 2007/0173794, US 2007/0173795, US 2007/0185475, US 2010/0004641, US 2010/0004643, US 2010/0022994, US 2010/002995, US 2010/0042079, WO 2007/084627, and WO 2007/084694, the entire disclosures of each of which are incorporated herein by reference. Further examples of such innovative and novel systems and methods are found in commonly assigned U.S. patent applications Ser. Nos. 12/840,818, 12/831,859, 12/831,845, 12/831,783 and 12/842,870, the entire disclosures of each of which are incorporated herein by reference.
In the treatment of cataracts, presbyopia, conditions of the eye, and afflictions of the eye, and in particular, in using lasers for such treatments, the determination of the position (relative to other structures of the eye and/or relative to any treatment equipment, such as a laser), and the shape of the structures of the eye is essential to allow the precise application of laser energy to effect the treatment. In general, greater accuracy and precision in making such determinations is beneficial. Further, visual images of these structures for the treating physician to observe can be beneficial and can enhance the outcome of any procedures. Accordingly, as provided in detail in this specification, improvements in the illumination of structures of the eye are provided herein, which improvements give rise to improved determination of the position and shape of structures within the eye, as well as, enhanced images of those structures.